Copper is an extremely important metal material in the national economic construction. With the rapid development of national economy, the copper resources which are easy to separate are getting increasingly scarce, more and more attention has been paid to the development and utilization of refractory copper resources. With the aim of realizing the efficient development and utilization of refractory chalcopyrite resources, extensive studies have been conducted by a number of research units and institutes. CN Pat. App. No. 200710180591.5 discloses a method for flotation separation of copper-sulfur, in which copper-sulfur separation of bulk concentrate is achieved at a pH of between 12.5 and 13, with the addition of combined depressor including calcium oxide, sodium sulfate and sodium cyanide. However, sodium cyanide is an extremely toxic reagent, the application of which will be detrimental to the sequential tailing treatment and the environment. CN Pat. App. No. 201010539277.3 discloses a method for copper-sulfur separations, in which sodium silicate or sodium sulfide acting as depressor is employed to accomplish the separation of copper from sulfur. CN Pat. App. No. 200710035482.4 discloses an efficient and environmentally friendly method for the separation of complex sulfide ores. Sulfide flotation is performed, one or more of oxalic acid, sodium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium bisulfate and ferrous sulfate acting as activator, yellow collector (xanthate), black collector (aerofloat), white collector (thiocarbanilide) and thionocarbamate acting as collector of sulfide ore, and BC acting as frother are added and agitated to disperse uniformly, in which case sulfide concentrate is recovered. Such processes are performed to achieve copper-sulfur separations on sulfide concentrate generally by using combined depressor or activator, and flotation reagents with high degree of selectivity.
Some of refractory copper ores have multiple natural types, such as chalcopyrite ore containing pyrrhotite, chalcopyrite ore containing pyrrhotite, talc and serpentine, chalcopyrite ore containing pyrite, copper skarn and so on. The chalcopyrite ore containing pyrrhotite, talc, and serpentine, such as copper ore in Dongguashan is one kind of typical refractory ore. Based on variable characteristics of Dongguashan copper ores, there are alternative separation processes. For chalcopyrite ores which are free of pyrrhotite, talc and serpentine, they are treated using combined depressor and highly effective collector in the presence of xanthate, in which case sulfide ores are floated off to separate copper from other sulfide minerals. While chalcopyrite ores containing pyrrhotite, talc and serpentine are treated using combined depressor and highly effective collector to realize copper-sulfur separation. The processes have three disadvantages as follows: Firstly, although online analysis and inspection system are adopted in the flotation circuits, there is a certain lag between the changes occurred in differential separation processes, additionally, the separation processes often fail to reach steady state in time, causing it hard to obtain a steady metallurgical performance, both of which lead to lower separation efficiency and greater copper losses especially when changes in ores type are frequent. Secondly, talc exhibits excellent floatability, therefore increasing talc pre-flotation can effectively reduce the content of silicon and magnesium in the copper concentrate, whereas chalcopyrite is also readily floatable, and a portion of chalcopyrite is floated into the talc concentrate during the talc pre-flotation, which causes copper losses and lowers the recovery of chalcopyrite. Thirdly, even though the highly selective collector or combined depressor is employed, the metallurgical performance is still not very satisfactory, and the cost of flotation reagents is remarkably high.